84 THE ROTIFERA. 



the penis make very minute punctures in the skin, and that the rod-like spermatozoa 

 find their way through these. Such hypothesis scarcely requires serious notice ; but 

 I may mention that Mr. Brightwell, Mr. Gosse, Mr. Hood, and myself have all seen 

 coitus take place, in various Botifera, at the cloaca. 



Length. About y-^ inch ; lorica, yf^ inch. Habitat. Weedy pools ; duckweed ; 

 around London (P.H.G.) ; Sandhurst, Berks (Dr. Collins). 



S. SPINIGEBA, Ehrenberg. 

 (PI. XXII. fig. 2.) 



Salpina spinigera . . . Ehrenberg, Die In/us. 1838, p. 470, Taf. Iviii. fig. 5. 



[SP. CH. Occipital and pectoral spines scarcely diverse from tlw preceding ; lumbar 

 a long, slender, acute spine, slightly recurved; alvine pair slightly divergent and 

 decurved; sinuses separating the occipital from the pectoral, and the lumbar from the 

 alvine, with straight bottoms. 



The species of this genus are so consimilar that little more is needful than an 

 enumeration of the points of technical difference. These will be better discerned from 

 the figures than from verbal description. Though minute, they are constant, and I 

 think, therefore, specific. The most marked, here, is the production of the lumbar point 

 into a true spine in which the ridges meet, and which takes a direction different from 

 their outline. The sides have oblique corrugations ; and the general surface is coarsely 

 stippled in various degrees. The eye is large and pale red. It is certainly a rare form ; 

 yet I have met with it on various occasions. P.H.G.]. 



Length. Of lorica, r \^ inch. Habitat. Pools at Battersea Rise ; Hampstead Heath ; 

 Leamington ; on Ceratophyllum (P.H.G.). 



S. BREVISPINA, Ehrenberg. 

 (PI. XXII. fig. 4.) 



Salpina brevispina . . . Ehrenberg, Die In/its. 1838, p. 470, Taf. Iviii. fig. 8. 



[SP CH. Occipital spines wholly wanting ; pectoral pair short and straight ; 

 lumbar and alvine as in mucronata. 



The total lack of the pair of occipital spines to the lorica is a clear distinction of 

 this species, the anterior extremities of the dorsal carinse not sensibly projecting beyond 

 the level of its truncate front, which, however, is not quite a straight line. The dorsal 

 arch, and the lumbar joint which terminates it, are nearly as in mucronata, only the 

 point is much shorter, and the sinus between it and each alvine spine is circular. The 

 surface is delicately stippled or covered with impressed dots. The ventral plane of the 

 lorica has not that abrupt bulging, which marks both the preceding species ; the dorsal 

 is more strongly arched than in either. 



This species is sufficiently common in the fine-leafed aquatic vegetation of ponds and 

 ditches. Its manners are precisely such as have been recently described. I do not 

 know how to distinguish between this and the S. redunca of the same author. P.H.G.] 



Length. About T | ff inch. Habitat. Lakes and pools : very common (P.H.G.). 



S. MACRACANTHA, GoSSC, Sp. nOV. 



(PI. XXII. fig. 6.) 



[SP. CH. Occipital spines u- anting ; pectoral pair short, straight; lumbar spine 



and alvine pair long , straight ; the latter much longer than the former ; the anterior 

 and posterior ends of the ventral side of the lorica deeply excised ; lorica- surf ace not 

 stippled. 



The lorica of this fine species is ventricose ; the dorsal cleft is widely gaping. The 

 lumbar union of the carinte forms a true spine comparatively long and slender, yet is 



