ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 243 



body is imbedded in the coenosarc of a Gerardia ; the " carapace " is 

 formed of two scales or valves united along the middle line. On the 

 side opposite to the adherent edge there is an orifice, which is probably 

 only the remains of the separate condition of the two valves, which 

 obtained during its Cypris stage. The " hilum " of the kidney-shaped 

 body corresponds to the anterior or abdominal face ; the head of the 

 animal is close to the deepest point of the hilum, and the tail corre- 

 sponds to the opening of the carapace. Originally, no doubt, the 

 carapace was attached by the dorsal portion intermediate between the 

 head and the abdomen. The body is little more than one centimetre 

 long, and the carapace is two, three, or four times as long as it. 



This carapace is hard and cartilaginous externally, and is limited 

 internally by a soft layer ; between these there is lodged the liver and 

 one of the genital glands, together with a very rich vascular plexus. 

 The external covering is riddled by a large number of small ducts, 

 the outer orifices of which are covered by a membrane, which is sur- 

 rounded by delicate filaments ; these are of cartilaginous consistency, 

 and have a central duct. They appear to be formed of the general 

 connective tissue : the canaliculi given off from the duct pass into 

 the base of the filaments. 



A study of the circulatory organs shows that the tissues on the 

 inner face of the carapace are supplied with a rich capillary plexus, 

 which surrounds all the organs, and gives rise to nutrient lacunae. 

 These communicate with the internal orifices of the canals, so that we 

 may say that Laura gives off thousands of radicles, which force their 

 way into the tissues of the Gerardia. The peculiar arrangements of 

 the digestive system confirm this view. 



Passing over other points in the carapace, we come to the body of 

 the animal. This consists of eleven rings, or twelve if we count the 

 two caudal valves as a ring. The first two are smaller than tbe suc- 

 ceeding four ; the whole body is S-shaped in form, but the superior 

 curvature is stronger and larger than the inferior. The eleventh 

 ring ends in four large unequal cirri. There are six pairs of limbs, 

 of which the first five have more function as accessory reproductive 

 than as locomotor appendages. The first five appear to be on the first 

 five segments ; the sixth are near the anal extremity. 



The digestive system is described in detail. We have here only space 

 to say that the liver is of great size, that buccal and anal orifices appear 

 to be absent, and that the digestive tube is always full of a yellow, 

 pultaceous matter, which appears to be similar to the hepatic secre- 

 tion. After describing the circulatory arrangements, the author points 

 out that direct alimentation probably does not obtain in this creature ; 

 absorption is effected by the carapace; the absorbed products are 

 purified by the biliary secretion, which here at any rate appears to 

 have a depuratory function. 



There are four pairs of testicles, which are placed at the base of 

 four pairs of legs. The ovary is found in the carapace, and the 

 ducts open on the first pair of legs. The animals are truly herma- 

 phrodite, and fecundation appears to be accomplished within the 

 carapace. The young have a Navjplius-sta^a. 



