24 Dr. A. C. Stokes on some 



Salpina simtlis, sp. n. 

 (PI. VIII. figs. 14, 15, 16, 17, and 18.) 



Lorica much as in Salpina hrevrspina^ Ehr. Occipital 

 spines entirely wanting ; the pectoral pair short, acute, wide 

 at base and strongly curved upward (fig. 14) ; posterior spines 

 long and conspicuous, the alvine pair nearly twice as long as 

 the lumbar one, with a slight upward curve, the lumbar being 

 at the termination of the' dorsal cleft and slightly recurved ; 

 entire surface finely stippled, a broad coarsely punctate band 

 or collar surrounding the frontal region (fig. 14) ; dorsal cleft 

 (fig. 1%) narrow, elastic, with a deep depression at its frontal 

 termination, its lateral borders sloping outward from a straight 

 base ; lateral antennas present near the posterior border 

 (figs. 15 and 16), the nerve-fibre prominent, at first filiform, 

 whence it conspicuously widens to become again thread-like; 

 frontal antenna lobe-like ; brain large, its latero-ventral 

 region appearing to bear several fusiform lobes ; mastax 

 globose ; oesophagus long, variously curved, and lined by 

 long, conspicuous, flagella-like cilia, which are pendent within 

 the stomach and plainly distinct from its lining of short fine 

 cilia; a gastric gland attached on each side to the antero- 

 inferior region of the stomach ; ovary ventrad, extending 

 transversely to the stomach and the intestine ; contractile 

 vesicle nearly one half as long as the lorica, and, when fully 

 dilated, crowding the ovary forward against the gastric 

 glands ; two small, broadly ovate, ventral glands, one on 

 each side near the posterior extremity, apparently foot-glands. 



Length, including toes, 7^5 inch. 



The points of difference between this species and the Salpina 

 brevispina of Ehrenberg are the long posterior spines, the 

 acute, curved pectoral spines, the deep, broad, more or less 

 rectangular, dorso-frontal emargination, and the long oesopha- 

 geal flagella, which are so obtrusive that they could not be 

 overlooked if they were present in S. brevispina. S. similis 

 is twice as large as >S'. brevispina. 



In a single instance, and entirely by accident, while sub- 

 jecting the Rotiferon to pressure, living spermatozoa were 

 forced from the cloacal orifice into the surrounding water, 

 where they soon died. When viewed with insufficient magni- 

 fying power each spermatozoon seemed to be a minute sphere 

 with a single long flagellum ; but this is by no means certain. 

 The seminal receptacle was not seen. 



A somewhat smaller variety of this species occurs in the 

 same pool. It differs from the foregoing in having the 

 pectoral spines straight (fig. 18), the alvine and the lumbar 



