. Bihang till Kongl. Svenska vetenskaps-akademiens handlingar. Science; Botany. 128 SVEN LOVEN, ON THE ECHINOIDEA DESCRIBED BY LINN^ marginal tertiaiy tubercles on the interradia is seen in all the Diadematidse. In Centrostephanus therc are three such series between the zone and the primor- dial series of tubercles. It is readily seen that LiNN^^us regarded the Echi- niis Diadema as the prin- cipal species of the two, and that he first drew up Part of the ambulacrum of E. Diadema. itS description from the showiag the lateral series of larger Ijn-aer and more instnic- tertiaries. , '^ tive
. Bihang till Kongl. Svenska vetenskaps-akademiens handlingar. Science; Botany. 128 SVEN LOVEN, ON THE ECHINOIDEA DESCRIBED BY LINN^ marginal tertiaiy tubercles on the interradia is seen in all the Diadematidse. In Centrostephanus therc are three such series between the zone and the primor- dial series of tubercles. It is readily seen that LiNN^^us regarded the Echi- niis Diadema as the prin- cipal species of the two, and that he first drew up Part of the ambulacrum of E. Diadema. itS description from the showiag the lateral series of larger Ijn-aer and more instnic- tertiaries. , '^ tive specimen, and then that of the other, the E. saxatilis, treating this less circum- stantially and rather summarily. He says it closely re- sembles the E. Diadema, but is of a smaller size. Its pri- marv tnbercles he describes as formino- four, not six series in every interradium, but »castera eadem», that is: their ma- melons are perforated as in that species. From this cha- racter, which is set down as common to both, being distinc- tive of the Diadematidse; from the resemblance of the tAvo species to each other insisted upon throughout, and from the care that is taken to keep them jointly apart, it follows that the Echinus saxatilis L. is also a member of that group. While in the E. Diadema the ambulacra, that is the zones, are combined by pairs iuto five »radii», convex, elevated and lanceolate, they are simply counted separately as ten in the E. saxatilis, the pairs only being approximated. In both spe- cies the ambulacra present two vertical series of tubercles, but in the interjacent space there are in the E. saxatilis two series of tertiaries, not four. Unlike what is said of the pores in the E. Diadema it is here stated that they are placed in a double row, that is a simple row of geminous pores, and are met with also on the ventral side, »subtus etiam obvii», which cannot but mean that they are there arranged in the same manner, or nearly so, as on the dorsal sid
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Keywords: ., bookcentury1800, booksubjectbotany, booksubjectscience, bookyear1
