Brachionaea.'] INFUSORIAL animaicules. 679 



except in B. militans, whoi'c it is simple and conical fcodogastricaj ; 

 and two biliary glandi=!, variously modified in form, present in all. 

 Seven species exhibit glands, a contractile vesicle, and an ovarium ; 

 in the others, their roughness precludes those organs being satis- 

 factorily perceived. No species is viviparous. All of them carry 

 their eggs attached, often as many as eight or ten at a time. B. pala 

 allows the eggs of another creature to be attached to its back, which 

 it carries about until the young creep out. Traces of a vascular 

 system are indicated in all by the presence of a respiratory tube in the 

 neck ; in B. pala are ti'ansverse vessels, and in four species from six 

 to eight tremulous giU-like organs are attached to the sexual glan ds 

 Of the nervous system, the chief ganglion, that beneath the red eye, 

 is distinct in all. In four, the pigment of the eye is inclosed in a 

 sharply four-cornered cell (as in Cyclops), of apparently two cells 

 connected together laterally. In the cell the pigment is variously 

 distributed, so that, in a physiological sense, there is no lens or 

 cornea. In B. pala, B. urceolaris, and B. ruhcm, sometimes increase 

 in such quantities as to render the water milky and turbid. Several 

 species are infested with Vorticella, Epistylis, and other parasites, 

 which attach themselves to their shells. 



Bb^vchioxus pala. — Lorica smooth, with four spines in fi'ont, and 



two obtuse ones near the opening for the foot. This creature swims in 



a perpendicular position, the brow being directed upwards. Each 



jaw has five teeth ; the alimentary canal, being constricted, forms a 



• stomach. Length l-36th; lorica only l-48th. 



B. amphiceros. — Has a smooth lorica, with four spines, both in 

 front, and posteriorly ; four sharp posterior teeth arc characteristic. 

 Length l-72nd. 



B. urceolaris {Brachiomis urceolaris, M.) — Whitish, lorica smooth, 

 with six very short spines in front, posterior extremity rounded ; 

 lorica slightly granulated; its points are shorter and less sharp 

 than in the following species ; delicate longitudinal ridges proceed 

 from the spines ; the jaw shave each five teeth. Both sexual glands 

 and contractile vesicle, as well as an ovarium, are seen. Found in 

 fresh and brackish water. Length l-96thto l-72nd. 



B. rubens {JJrachionus urceolaris, M.) — Lorica smooth, with six 



