THE CIRRIPEDS. ALIMENTARY CANAL. CCELOM. 



411 



pidse and eight in the cryptophialidae. In apodous forms only the jaws and one 

 pair of antennae are retained, while in the rhyzocephalidae all traces of the appen- 

 dages disappear. 



Alimentary Canal. — The stomodEeum is generally small, and leads into a 

 large pear-shaped enteron provided with prominent gastro-hepatic glands. (Fig. 

 275.) The larger ones form a circle of racemose diverticula, or pouches, said to 

 be provided with two kinds of cells, hepatic and pancreatic, h.d. and g.h. Circular 

 bands of smaller pouches, or patches of cells having a special structure, are ar- 

 ranged at regular intervals over the remainder of the stomach, diminishing in 

 distinctness toward the caudal end, h.c. The ^i. m, 



anus, a, is located on the haemal side of the 

 elongated caudal lobe. 



Ccfilom. — True ccelomic chambers are well 

 developed in the cirripeds and copepods. In 

 Lernaea ten pairs, one apparently for every 

 metamere except the first, have been described 

 by Pedaschenko. (Fig. 279, A.) They form 

 large segmentally arranged chambers enclosed 

 in thin but well defined epithelial walls. They 



Fig. 277. — Petrarca mira (after Fowler); 

 commensinal in the mesenteric chamber of the 

 coral Bathyactis. Ramifications of testis, ovary, 

 and liver in the mantle folds. 



Fig. 278. — Ibla quadrivalis, male; parasitic 

 on the female, within the palial chamber. (From 

 Gruvel, slightly modified 3-4 mm. long.) 



are completely shut off from the remaining parts of the primitive coelom, or 

 haemocoele, which consists of irregular, extensive, unsegmented spaces that are 

 surrounded by mesoderm and contain free mesodermic cells. 



In the adult cirripeds three pairs of ccelomic chambers have been recognized, 

 although their early history and identity are not known. (Fig. 279, B.) There 

 is a small pair of completely closed sacs in the head region, lined with excretory 

 cells that probably represent the remnants of the antennary coelom and the anten- 

 nary gland, c\ The second pair lie in the thoracic or circumoral region, on 

 either side of, and close to, the stomach, c^ They are extensive chambers that 

 communicate with each other across the median line, in front of and behind the 

 mouth (Gruvel). They are completely separated from the haemocoele, but open 



