ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 427 



- It occurs on the outside of the gut, ensheathed in layers of endo- 

 thelium and connective tissue formed by its host. Occasionally one 

 was found free in the ccelom. Apart from the epithelium and muscula- 

 ture of its body-wall, the parasite has no organs except the gonads. 

 These occupy the central cavity which has a " ciliated canal " as its 

 only communication with the exterior. 



The development occurs within the mother, and the segmentation 

 and larvae are Gasteropod-like. The larva has velum, otoliths, foot- 

 glands, a shell, an operculum, &c. The post-embryonic development 

 occurs within the connective tissue of the wall of the gut, and there is 

 a gradual protrusion into the coelom. 



What intervenes between the stage when the minute larva is within 

 its parent and the stage when it occurs in the wall of the gut, is un- 

 certain. There are some reasons for believing that the larva must be 

 liberated from its first host before the post-larval changes occur. 



The new parasite is compared in detail with Entoconcha mirabilis 

 and Entocolax ludwigi. 



Crystalline Style and Style-Sac in Turritella communis.* — 

 W. B. Randies finds that the stomach of this gasteropod contains a 

 crystalline style and style-sac, and has on the inner wall of the posterior 

 chamber a short crescentic groove somewhat similar to that in Trochus, 

 and probably representing a vestigial spiral caecum. If so, it indicates 

 the retention of a very primitive character in this genus. 



Paryphanta hochstetteri Pfr.f — B. Beutler gives an account of the 

 structure of this rare New Zealand snail, which does not however show 

 any remarkable peculiarity. Its affinities are with Testacella which in 

 many ways it closely resembles ; as it has a relatively large shell it is 

 probably ancestral to the Testacellids where the shell becomes rudi- 

 mentary. 



' Talisman ' Opisthobranchs.ij: — A. Vayssiere reports on the small 

 collection made by the 'Talisman' in 1883. As Opisthobranchs are 

 notably littoral, it was not surprising that only seven forms were ob- 

 tained in the deep dredgings. Although they had lain many years in 

 spirit, they admitted of dissection, and the author has obtained some 

 interesting results. In this preliminary note he directs particular 

 attention to Phyllidiopsis berghi sp. n. 



Arthxopoda. 



Last Joint of the Limbs in Arthropods.§ — J. C. H. de Meijere 

 has made a detailed comparative study of the terminal joint in the 

 appendages of insects, Crustaceans, Arachnoids, Pycnogonids, Limulus, 

 Peripatus, &c. From the nature of the subject it is not easy to make 

 an intelligible summary. 



Ventral Integument of Trilobites.|| — C. E. Beecher has especially 

 studied Triarthus becJci Green, but refers also to AsapJius megistus 



* Anat. Anzeig., xxi. (1902) pp. 200-3 (3 figs.). 

 + Zool. Jahrb., xiv. (1901) pp. 369-416 (4 pis.). 

 I Comptes Kendus, cxxxiv. (1902) pp. 296-7. 

 § Zool. Jahrb., xiv. (1901) pp. 417-76 (8 pis.). 

 i Amer. Journ. Sci., xiii. (1902) pp. 165-74 (4 pis.). 



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