. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. r> Developement of the spermatozoa in Lumbricus. the Helicinae (fg. 387. A,). According to analogy with the higher animals the sperma- tozoa are also unquestionably produced in an endogenous way, and, as is shown by the ob- servations ofIio/li/ier-\- on the clevelopement of the spermatozoa in Lumbricus and Distoma, in the interior of the nuclei. We cannot, however, trace the process of formation with decisive certainty owing to the smallness of the elements in question. The external ap- pearance (B) leads us, however,
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. r> Developement of the spermatozoa in Lumbricus. the Helicinae (fg. 387. A,). According to analogy with the higher animals the sperma- tozoa are also unquestionably produced in an endogenous way, and, as is shown by the ob- servations ofIio/li/ier-\- on the clevelopement of the spermatozoa in Lumbricus and Distoma, in the interior of the nuclei. We cannot, however, trace the process of formation with decisive certainty owing to the smallness of the elements in question. The external ap- pearance (B) leads us, however, to infer that the cellular formations grow out into a long fibre. The cells gradually assume a fusi- form shape, but still remain united toge- ther in one group. It is the peripheric end which seems to get extended in forming the spermatozoa. Wherever a central ball oc- curs, for instance, in Lumbricus and Hirudo, the group of cells at this stage of the deve- lopement presents a very pretty appearance. The spermatic fibres radiate towards all directions from the central ball, into which their thickened extremity is inserted; they have then made their exit in a still imperfect state (c). They soon, however, get grouped together into bundles, the points of the fibres, gradually converging towards one common point (D); the central ball in the meantime gradually dissolves. Similar fasciculated groups are likewise seen in the spermatozoa of Annelids in most cases even where the central ball is wanting — in the Trematoda, &c. for in- stance. The same facts we have already noticed when speaking of the Gasteropoda. We then proved that the separate elements in the groups of cells originate through the continued en- * AVatfner in Miiller's Archiv. 1835, S. 222. t Kolliker, Die Bilduus der Sanienfaden, u. s. w. VOL IV. dogenous formation from one single, and at first simple, cell. It is easily traceable that the same takes place in the Annelida, when we compare the different
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