GENUS COTHURNIA. 721 



with the size of the lorica, but little exsert beyond its margin when 

 extended. Length of large-sized lorica 1-190". 



HAB. Fresh water, on various Entomostraca, but more especially abun- 

 dant on the branchial appendages of the fresh-water crayfish, Astacus 

 fluviatilis. 



Cothurnia astaci, Stein. PL. XL. FIG. 26. 



Lorica urceolate, about twice as long as broad, the posterior half 

 rounded and slightly ventricose, narrowest and contracted behind the 

 slightly everted and even anterior border ; colourless or pale yellow ; 

 pedicle thick, short, slightly curved, transversely plicate ; animalcule 

 slender, subcylindrical, protruding some distance beyond the margin of 

 the sheath. Length of lorica 1-288". 



HAB. Fresh water, on Astacus fluviatilis and various Entomostraca. 



During a fatal epidemic among the fresh-water cray-fish of Lombardy and 

 Venetia in the year 1863, it is reported by Ninni* that the dying Crustacea were 

 completely infested with an Infusorium, referable to the genus Vaginicola, probably 

 identical with the present species, its abnormal development on the branchial 

 appendages apparently producing the death of the crustacean through asphyxia. 



Cothurnia curva, Stein. PL. XL. FIG. 27. 



Lorica gibbous, ventricose posteriorly, curved to such an extent ante- 

 riorly as to impart to the aperture an oblique direction ; transparent when 

 young, but of a dull rusty-red colour in the adult state ; animalcule agreeing 

 in form with C. astaci and C. Sieboldii but not protruding to so great a 

 distance beyond the orifice of the lorica. Length of lorica 1-360". 



HAB. Fresh water, attached to various Entomostraca. 



Stein rather doubts whether this species may not be considered as a distorted 

 variety of C. astaci. The author, however, is inclined to regard it as an independent 

 type, having found it abundantly at different times upon Canthocamptus minutus in 

 the neighbourhood of London. In all instances the curved or gibbous contour of the 

 lorica was constant, and the animalcules were never observed to protrude themselves 

 to that distance beyond the orifice of the aperture which has been described of 

 C. astaci. On one occasion a lorica was met with in which numerous spore-like 

 bodies, probably representing the reproductive gemmules of the former occupant, were 

 found attached by a short peduncle or funiculus to the bottom of its internal cavity. 

 A species so closely resembling the present form that the same diagnosis serves for 

 its description, has been obtained by Professor Boeck attached to marine Ento- 

 mostraca on the coast of Norway. Claparede and Lachmann have proposed to 

 distinguish it by the title of Cothurnia recurva, but there does not appear to be 

 sufficient reason for regarding it as otherwise than a salt-water variety of the species 

 just described. The contour of the lorica in this type is perhaps slightly more 

 slender, and the curvature of the neck scarcely so strongly pronounced. 



Cothurnia nodosa, C. & L. 



Lorica transparent, subcylindrical, somewhat narrowed anteriorly, about 

 twice as long as broad, frequently with one or more symmetrical transverse 



* ' Atti del Imp. Reg. Istituto Veneto,' 1864. 

 VOL. II. c 



