. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. Fortunately a few specimens of Clistosaccus in my material contained near- ly fully developed embryos in the egg membranes and these are already provided with six appendages at each side of the abdomen (fig. , v ° Fig. 14. a, Clistosaccus pagun irom hupagurus pubescens, rhor , 61 15 9 35 \\ , 970 m. Larva 14 a)- The soon would in the egg membrane, taken from the mantle cavity, X 300; //, Sylon hippolytei from Spirontocan have hatched for thev DOS- lll,l'l'"'>''- "T
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. Fortunately a few specimens of Clistosaccus in my material contained near- ly fully developed embryos in the egg membranes and these are already provided with six appendages at each side of the abdomen (fig. , v ° Fig. 14. a, Clistosaccus pagun irom hupagurus pubescens, rhor , 61 15 9 35 \\ , 970 m. Larva 14 a)- The soon would in the egg membrane, taken from the mantle cavity, X 300; //, Sylon hippolytei from Spirontocan have hatched for thev DOS- lll,l'l'"'>''- "Thor", Stat. 171, 1901. Larva in the egg membrane, taken from the mantle cavity, • sess already all the peculiarities of the cypris stage. The size of the larvae is about 175 //, with the exception of the appendages little is to be seen of their structure. In the anterior region a pair of antennae is found and in the posterior part the pleopods. These have at their extremity strong swimming hairs. They do not have an eye or a pigmented spot in the anterior region of the body. The general shape of the larvae of Clistosaccus does not differ in important details from that of the cypris larvae of Sacculina (cf. Delage, '84) and from those of the genus Lepas. Family Sylonidae n. tarn. Body ovoid, long axis parallel to long axis of host. Stalk at the dorsal surface (the region where the visceral mass is united with the mantle). Two mantle openings, developing at a rather late stage, in the anterior part of the dorsal surface, left and right of the median plane. Colleteric gland unpaired, in the posterior part of the visceral mass, at the ventral side. Testes unknown. The structure of the animals belonging to the genus Sylon is so strikingly different from that of the other Rliizocephala that there is sufficient reason to place these parasites into a separate family. The nearest allies of the Sylonidae probably are the Clistosaccidae. Especially the colleteric gland in both fam
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectarcticregions
