ASPLANCHxNAD.E ; SYNCH.ETAD^. 17 



sac-like ; head depressed with a thin, downwards pointimj, projecting process on its mid- 

 dorsal edge ; corona a simple, marginal circle. 



" This ' bonnie gem ' was discovered among Utricularia and Lemna in a small pond 

 shaded by alders and swamxj-maples. The animal is an ovoid, hyaline sac, constricted 

 anteriorly to a short cylindrical neck, which, when the corona is retracted, is fluted, and 

 the free edge is crenate. There is on each side a sub-dorsal groove. The corona has a 

 circlet of ample ciha, and at the dorsal border there is a conspicuous spatula-shaped apex, 

 which, seen laterally, is thin and turned downwards ; on each side of this is what appears 

 to be a stout incurved seta. The stomach is large and lobed, of a rich yellowish 

 brown. Themastax is an oblong clear globule, the apex of which is pushed to the fi'ont ; 

 the tropin appear to be virgate. There is a large nearly globular contractile vesicle, 

 which is situated near the posterior wall ; as it collapses, the extremity of the sac caves 

 in, and occupies in part the space it filled. The large red eye is circular (fig. 23 b) seen 

 dorsally, and concavo-convex seen obliquely from below. Dorsally viewed there is a 

 brilliant circular centre, particidarly when illuminated fi'om the mirror below ; seen 

 laterally there is disclosed a clear sphere (fig. 23 c) in the centre of the concave lower 

 face : this seems to act like a lens." 



Length, ^^jj inch; width, ^^ inch. Habitat. Corunna, Michigan (Kellicott). 



Sacculus geemanicus, Leydig (PI. XXXII. fig. 25). 

 Ascomorpha germanica . . . Leydig (110). 



SP. CH. Dorsal view sac-like ; head conical, tuith a triangular "projecting process 

 on the mid-dorsal edge of its base; corona a simple marginal wreath, tuith several long 

 styles set at intervals. 



It is with some hesitation that I give these specific characters taken ft-om Leydig's 

 description and figures. He himself notices three points of difference between germanicus 

 and Ascomorpha helvetica (S. viridis), viz. that its coronal head is orange yellow, that 

 its size is half that of viridis, and that its motions are peculiar — very similar, indeed, to 

 those of saltans. His figure shows another peculiarity, namely the projecting of the 

 back in a sort of triangular beak. He adds that he had seen as many as six roimd eggs 

 (evidently male eggs) attached to one individual ; but that those, which carried the rough 

 ephippial eggs, never had more than one at a time. 



Length, ^ inch. 



The SP. CH. for Sacculus vieidis have not yet been given (vol. i. p. 124), as it 

 was described as the solitary species of the genus. They are as follows ; — 



Dorsal view sac-like ; ventral view unsy^nmetrical with a gibbous dorsal outline ; 

 head conical, ivithout a mid-dorsal process on the edge of its base ; corona a simple 

 marginal circle, with several long styles set at intervals. 



SYNCH.ffi;TA LONGiPES, Gosse (169), (PL XXXI. fig. 4 '). 



[SP. CH. In front mtich like S. pectinata, but luith the foot distinct, separated, 

 long, furnished with tivo small toes. 



The well-marked foot, having a rhomboid outline, common to all the eight or ten 

 specimens that I examined, appeared to me sufficient, when combined with its small 

 dimensions, to distinguish this species from S. pectinata, with which else it has much in 

 common. The broad head bears four frontal warts and two sette. It has occurred in 

 some profusion in fresh water near Dimdee. A great, occipital brain carries a well- 

 defined eye, which appears black. The foot is capable of retraction as far as its angle, 

 and is occasionally twitched up and vibrated. 



Length, ^j^ inch. Habitat. Fresh-water, Dundee. P.H.G.] 



' Mr. Hood (177) says that Mr. Gosse's figure has been taken from a young animal. 



