COLUEID^. 47 



dered uneven by fine depressions ; and the posterior end of the crest projects somewhat 

 beyond the base of the foot. 



Length (of lorica), .t^^ inch. Habitat. Berlin (Ehr.). 



Metopidia cobnuta, Schmarda (PI. XXXIV. fig. 3). 

 Lepaddla comuta Schmarda (135). 



SP. CH. Lorica oval ; its anterior margin with ttvo great spines. 



Body yellowish grey. A deep gap separates the two curved frontal horns. The 

 unci are one-toothed. Schmarda says that there are two contractile vesicles at the 

 foot ; and he draws two small vesicles in that position. Unfortunately he does not say 

 whether he has seen them contract or not ; nor whether they did so mdependently of 

 each other. The only similar case of such a construction, that I am acquainted with, 

 is that of Conochilus volvox (according to Cohn, vol. i. p. 90, foot note). 



Length (total), pj^ inch. Habitat. Brackish water. New Orleans (Schm.). 



Metopidia oblonga, Ehrenberg (PI. XXXIV. 5). 



Sguamclla oblcmga Ehrenberg (42). 



SP. CH. Lorica elliptical, or ovately oblong, hyaline ; toes long, slender ; eyes 

 fo7ir. 



There are two or three teeth in each uncus ; the gastric glands are pear-shaped ; 

 and there are four frontal eyes arranged in the angles of a parallelogram. Ehrenberg 

 has seen a contractile vesicle, and lateral canals. 



Length (total), Tr|u inch. Habitat. BerUn (Ehr.). 

 Hexastemma melanoglbna, Lepadella muceonata, L. setifeea, Squamella 

 QUADEiDENTATA, Schviarda (135). These possibly may be Metopidia, but see note 1, 

 Supt, p. 8. 



MoNUEA DULCis, EJireubcrg (42), (PI. XXXIV. fig. 9). 



SP. CH. Lorica ovate, obliquely truncate behind, acute ; eyes distant. 



The dorsal outline (a long narrow oval, trmicate at both ends), the pointed termina- 

 tion of the lorica (seen at the side view), and the wide separation of the eyes, sufficiently 

 distinguish this species ; which, Ehrenberg thought, might be marine as well as lacus- 

 truie. 



Length, ^jj^ inch. Habitat. Near Berhn ; possibly Cattaro (Ehr.). 



Genus DISPINTHERA, Gosse (171). 



GEN. CH. Body sub-cylindric, inclosed, in part, within a lorica opien in front and 

 in rear, apparently cleft doivn the venter ; head and foot habitually protruded ; head 

 distinct, protected by horny plates, but loithout a frontal hook; two cervical eyes. 



DispiNTHEEA CAPSA, Gosse (171), (PI. XXXI. fig. 48). 



[SP. CH. Lorica in most parts soft a7id flexible ; foot stout ; toes two, furcate, 

 thick, straight, tapering, acute. 



This apparently new form I found in the sediment of water dipped by Mr. Bolton 

 from " ditch No. 2," in Sutton Park, Birmingham, crowded with fine Desmidiere. The 

 facies strikes one as very peculiar, and difficult to explain. The front is capable of 

 much protrusion, in a conical form, where a globose tubercle is visible, but only occa- 

 sionally, and a similar one, but more constant, on the occiput (or rather crown of the 

 head), just below the point of the occipital sheath. The lorica is discernible chiefly 

 about the head ; it tliere projects into several points, which seem very flexible, but 

 constant. When the head is far retracted (which is seldom), an array of spears is left 

 bristling up. Now and then, at the pectus, the integument is seen to fall into a flap, or 



