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 Rotifera, at the cloaca. 
Length. About ,3, inch; lorica, 1, inch. Habitat. Weedy pools; duckweed ; 
around London (P.H.G.); Sandhurst, Berks (Dr. Collins). 
§. sprinicEra, Ehrenberg. 
(Pl. XXII. fig. 2.) 
Salpina spinigera 5 . 5 Ehrenberg, Die Infus. 1838, p. 470, Taf. lviii. fig. 5. 
[SP. CH. Occipital and pectoral spines scarcely diverse from the 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,;4,5 inch. Habitat. Pools at Battersea Rise ; Hampstead Heath ; 
Leamington ; on Ceratophyllwm (P.H.G.). 
8. BREVISPINA, Hhrenberg. 
(Pl. XXII. fig. 4.) 
Salpina brevispina " . 3 Ehrenberg, Die Infus. 1838, p. 470, Taf. lviil. 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 carine 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. redwnca of the same author.—P.H.G.] 
Length. About ,4, inch. Habitat. Lakes and pools: very common (P.H.G.). 
S. MACRACANTHA, Gosse, sp. Noy. 
(BLS xox eG.) 
[SP. CH. Occipital spines wanting ; 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-surface not 
stippled. 
The lorica of this fine species is ventricose; the dorsal cleft is widely gaping. The 
lumbar union of the carinz forms a true spine comparatively long and slender, yet is 
