DE. LEIDY.— MISCELLANEA ZOOLOGICA. 67 



Fig. 8. Lateral view of the genito-anal prolongation ; the penis protruded, and the anal prolongation 

 drawn upwards : a. genital prolongation ; h. anal prolongation ; c. the uncinated portion of the penis ; 

 d. the spoon-like portion of the penis ; e. genital uncae ; f. caudal sette. 



Fig. 9. Female generative apparatus magnified : a. ovary ; b. oviduct ; c. vagina. 



Fig. 10 a. exhibits the relative position of an ovum within its tube magnified ; b. an ovum, magnified, 

 exhibiting the peculiar markings. 



Fig. 11. Posterior view of the genito-anal prolongation: a. genital prolongation; b. undeveloped uncce ; 

 c. caudal setae; d. anal prolongation. 



Fig. 12. Odoriferous glands, with the ventral cord concealing in its course the point of their termination. 



Fig. 13.1 Nervous system magnified: a. cerebral ganglia; b. optic ganglia; c. optic nerves; d. frontal 

 ganglion ; e. respiratory ganglia ; /. cerebellum ; g. branches within the prothorax ; h. nervous mass, 

 formed by the fusion of the abdominal with the remaining thoracic ganglia, within the mesothorax ; 

 i. antero-lateral branches ; k. postero-lateral branches ; /. posterior branches. 



Fig. 14. Antenna of Perthostoma. 



Fig. 15. Ova of Perthostoma, from the back of the female. 



MISCELLANEA ZOOLOGICA. 

 BY JOSEPH LETDY, IM. D. 



1. Description of a new ge)ius and species of Entozoa. Crypiohia helicis.* 



In September, 1846, I first gave an account, in our Proceedings, of the discovery 

 of a new genus and species of Entozoa inhabiting the fluid contained within the 

 vessie copulatrice or spermatheca of Helix albolabris, tridentata, and alternata. Since 

 then I have verified the observation, and have also detected it in several other species 

 of Helix, viz. elevata and tliyroidus; and also in a species of an allied genus, Bidimus 

 decollatus. 



The name which I gave it at that time, I was not aware, had been previously 

 applied to a genus of Insecta brachelytra, with the only difference of the latter 

 having the neuter termination " urn." I will therefore change the name to — 



Cryptoicus, minutissimus ; forma mutabilissima ; organisatione interna cellularum et granulorum. 



■C. helicis. Coloris expers ; forma plerumque elongata, ellipsoidi, fusiformi, vel ovata ; caudis duabus 

 adversis, una longiori quam altera. Structura interna stomachos duos et granulos numerosos parvos 

 exhibet. Long. ^1-^ — 1^5 li"- Habitat in spermatheca vel " vessie copulatrice" Helicis albolabris, 

 tridentatae, &c., et Bulimi decollati. 



* Proc. Acad. Nat. Sci., vol. iii. p. 100. 



