ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 585 



one segment has occurred — a phenomenon which we find in its complete 

 form in the family of Capitellidfe." 



"~ New Leech.* — Mr. J. Percy Moore describes as Microbdella bian- 

 nulata g. et sp. n., a leech obtained in North Carolina, U.S.A., on the 

 salamander, Desmognathus nigra. The leech is specially interesting on 

 account of the structure of the somites, which consist of two annuli only. 

 The new form belongs to the Glossiphonidfe, but is apparently the 

 smallest species of the family yet described, being only 4-5 mm. in 

 length in the half-expanded condition. The special interest is the 

 light it appears to shed on the difficult problems connected with the 

 segmentation of leeches. Nineteen segments are clearly indicated ex- 

 ternally ; they are biannulate except in the extreme anterior and 

 extreme posterior regions, and correspond to well-developed internal 

 partitions, as well as to the arrangement of the segmentally repeated 

 internal organs. If this leech is to be regarded as a primitive form, 

 then Whitman's views as to the typical number of annuli in a leech 

 somite, and the relation of the nerves to the annuli, must undergo con- 

 siderable modfication. The author discusses the point in some detail, 

 and concludes that the triannulate condition has been derived from the 

 biannulate. Therefore the fact that in leeches in general the anterior 

 and posterior somites have fewer annuli than the median, shows that 

 these segments are " type somites," rather than " abbreviated somites " 

 as they are regarded by Whitman. 



Cocoon of Piscicola and Herpobdella.f — E. Brumpt has made many 

 observations on copulation and oviposition in Piscicola geometra, Herpo- 

 bdella atomaria, and H. vulgaris. In the first the egg-laying occurs in 

 March and April on aquatic plants, stones, &c. The leech presses the 

 secretion of the turgescent clitellum against the object, it waits till adhe- 

 sion has occurred, and then creeps backwards out of the annular cocoon. 

 But the movements, which last for about 5 minutes, are such that an 

 invagination of the cocoon is effected, and this seems to be of importance 

 for the securing the purity and preservation of the contents. 



In Herpobdella the oviposition lasts about 20-25 minutes ; the cli- 

 tellum having been fixed, the leech rolls round and round, liberates a 

 number of eggs and some liquid into the cocoon, and slowly disengages 

 itself. There is the same invagination of the cocoon, the leech solving 

 the problem of creeping through an albuminous mass without introducing 

 any impurities into its interior ! 



Neuroglia in Invertebrates.^ — Dr. H. Joseph, in a brief note upon 

 Mulder's § recent paper on the neuroglia of Chordata, states that he has 

 made a somewhat similar series of preparations of the neuroglia of 

 Invertebrates, especially worms, and finds that conditions practically 

 identical with those described by Miiller for Vertebrates also occur 

 there. That is, he finds that the neuroglia has a fibrillar structure, and 

 the fibrillse are to be regarded as differentiated cell-prolongations. Glia 

 fibrillae not in connection with cells probably do not exist. Generally it 



* Proc. Acad. Nat. Sci. Philadelphia, 1900, pp. 50-73 (1 pi.). 

 t Bull. Soc. Zool. France, xxv. (1900) pp. 47-51 (4 figs.). Cf. this Journal, ante, 

 p. 327. X Anat. Anzeig., xvii. (1900) pp. 354-7. 



§ Cf. this Journal, ante, p. 22. 



Oct. 17th, 1900 2 R 



