ZOOLOGY. 577 



Adaptation to environment of Trematods. 



Professor Ercolani has publisbed a useful summary of facts in the 

 development of Trematods related to adaptation for environment. (1) 

 The succession of i^hases of development is not always the same in all 

 Trematods, some leaving the eggs as ciliated embryos requiring water, 

 and others as non-ciliated ones, developing in terrestrial gastropods ; (2) 

 the different phases of development are not the same for all encysta- 

 tion, e. g., being sometimes omitted ; (3) a special form of scissiparous 

 generation may occur e. g., in the racemose sporocysts where certain 

 living parts (as in Polyzoans and Hydroids) are connected by atrophied 

 stolons ; (4) the direct conversion of the tail of a cercaria into a nurse 

 sometimes occurs; (5) encystation may not only be normal, but also 

 accidental or abnormal. 



It is far from true that there is a determinate relation between Trem- 

 atods and Mollusks, and that the latter have only one species each ; 

 Bythinia tentaadata, e. g., has as many as twelve different species of 

 cercariae. (J. E. M. S., (2) v. 3, p. 784, from Arch. Ital. Biol, v. 1, p, 

 439-453.) 



NEMATELMINTHS. 



Diasche (Rich. von). Revision der in der Nematoden-Sanimlung des k. k. zool. Hof- 



Cabiuots befindlichen Original Exemplare Diesing's und Molins. Mit. 4 Taf. 



Verhandl. k. k. zool. bot. Ges. Wien, 1882, pp. 117-138. 

 Fourment (L.). Sur la vitality des Tricliines enkyst6es dans les viandes salves. 



Compt. rend. Ac. Sc. Paris, t. 94, p. 1211-1213. 

 M6gnln (P.). Sur de petits Helminthes aganies ekyst^s qui peuvent 6tre confondus 



et qui 1' ont 6t6 avec la Trichina Spiralis. Avec 3 pi. Bull. Soc. zool. France, 6. 



Ann. p. 189-198. 

 M^gnin(P.). Sur 1' organisation de la boucbe des Dochmius on Ankylostomes, apro- 

 pos de parasites de ces deux genres trouv^s cbez le cblen. Compt. rend. Acad. 



Sc. Paris, t. 94, p. 663-666. 

 Orley (L.). Report on the Nematodes in the possession of the Britisb Museum, with 



a review of the classification of the order. With 1 pi. Ann. & Mag. of Nat. Hist., 



(5,) V. 9, p. 301-318. 

 Orley (L.). Monographic der Anguilluliden. Mit. 7 Taf. Term^sz Fiizetek, v. 4, 



p. 154-177 (Deutsches Auszug d. ungar. geschriebenen Arbeit., p. 16-150). 

 Schulthess (Wilhelm). Beitrage zur Anatomic von Ankylostoma duodenale (Dubini)= 



Dochmius duodenalis (Leuckart). Mit 2 Taf . Zeitschr. f. wiss. Zool., 37 Bd., p. 



163-220. 



The Nematoid Worms. 



Dr. L. Orley has recently studied the Nematoids in the British Museum 

 and has come to the conclusion that there are three •' suborders " although 

 "there are perhaps few orders in which so continuous a series of forms 

 exists as in the Nematodes." His views as to the question of relationship 

 between parisitism and non-parisitism and classification may be gleaned 

 from his daignosis of the several groups. 



1. The Nematentozoa are " thread worms completing their early 

 stage in the free condition, their maturity as parasites in the bodies of 

 H. Mis. 26 37 



