ANUR^AD^. 125 



the lateral pair projects from the midst of a much thicker cylinder. There are two 

 square antennae. The eye is large, sparkling in sunlight, and refractile.— P.H.G.] 

 Length, y { j inch. Habitat. Near London ; Birmingham; Dundee (P.H.G.) : common. 



Genus NOTHOLCA, Gosse, gen. nov. 



[GEN. CH. Lorica ovate, truncate and six-spined in front, sometimes j^rodiiccd 

 behind; of two spoon-like plates united laterally; no hind spines; dorsal surface 

 marked longitudinally with alternate ridges and furrows ; expelled egg not usually 

 carried. Lacustrine and marine. 



The genus thus hidicated may include the species hiremis, striata, inermis (young ?), 

 acuminata, and foliacea (?) of Ehrenbcrg, together with others, which appear to be 

 hitherto midescribed. — P . H. G . ] 



N. ACUMINATA, Ehrcubcrg. 

 (PL XXIX. fig. 3.) 

 Anuraa acxaninata . . . Ehrenberg, Die Itifus. 1838, p. SOtj, Taf. Ixii. fig. 9. 



[SP. CH. 1,01100, produced behind into a long truncate point, spoon-shaped ; ven- 

 tral plate concave, one-third shorter than the dorsal. 



The form is very elegant. Of the frontal s-pines the antlers are nearly straight, the 

 laterals moderately long, the intermediaries very short. From their six points, and from 

 their five interspaces, run strongly marked lines throughout the lorica, of which the 

 former are elevated, the latter depressed angularly. The junction of the ventral plate 

 is about one-third from the point where the cloaca opens. Here two muscle-threads are 

 affixed, connected with the rectum, which they draw down. An ample contractile vesicle 

 receives on each side a conspicuous branchial duct, which in some parts is slender, in 

 others much expanded and corrugated, including many vacuoles, and carrying two 

 vibratile tags each. A remarkable structure is seen in apparent connection with these 

 organs, which recalls the pyriform sacs seen in Pterodina. The oesophagus is long, and 

 attached to it on each side is a small vessel which seems the ordinary gastric gland. 

 But somewhat behind these are seen a pair of sacs, connected with the stomach on each 

 side, and each giving off two threads, by one of which it is fastened to the lining mem- 

 brane of the lorica, while the other runs down for some distance parallel with, and close 

 beside, the tortuous vessel (branchia?), and is then attached to the interior, where two 

 remarkable shelly bosses are seen. The stomach itself is tied to the lorica by threads, 

 which are probably muscular. — P.H.G.]. 



Length, ^^ inch. Habitat. Ornamental waters near London (P.H.G.) : very rare. 



N. LONGisPiNA, Eellicott. 

 (PL XXVm. fig. 6.) 



Anuria longispina .... Eellicott, Amcr. J. Micr. iv. 1879, p. 20, with fig. 



„ „ . . . . (Abstracted) J. Boy. Micr. Soc. ii. 1879, p. 157, mth fig. 



„ ,,.... Levick, Midland Naturalist, ii. 1879, p. 241, 1 pi. 



„ spinosa .... Imhoff, Zool. Anzcig. Sept. 1883, No. 147, with fig. 



SP. CH. Lorica greatly produced behind so as to resemble a frontal spine; dorsal 

 and ventral plates commensurate ; of the six occipital spines the central pair consists of 

 one very long curved sjnne, and of one aborted straight spine ; the lateral piair, of two 

 long, and curved ; and the remaining pair, of two short, and straight ; the ventral plate 

 has a movable flap with a straight pectoral edge. 



' Notholca longispina does not readily lend itself to any theory on the cause of an 



