120 THE HISTORY OF ANIMALS. [u. V. 



the whole is like a lung ; of all the sponges this one is con- 

 fessed to have the most sensation, and to be the most 

 enduring. They are plainly seen in the sea near the sponges, 

 for the other sponges are white as the mud settles down 

 upon them, but these are always black. This is the mode 

 of production in sponges and testacea. 



CHAPTER XV. 



1. AMONG the malacostraca the carabi are impregnated by 

 sexual intercourse, and contain their ova during three 

 months, May, June, and July. They afterwards deposit 

 them upon the hollow part of their folded tail, and their 

 ova grow like worms. The same thing takes place in the 

 malacia and oviparous fish, for their ova always grow. 



2. The ova of the carabi are sandy, and divided into 

 eight parts ; for a cartilaginous appendage, round which the 

 ova are attached, is united to each of the opercula at their 

 junction with the side ; and the whole resembles a bunch of 

 grapes, for every one of the cartilaginous appendages is fre- 

 quently subdivided, and the divisions are apparent to any 

 one who will separate them, but when first seen they 

 appear to be united. Those ova which are in the centre 

 are larger than those which are contiguous to the perforation, 

 and the last are the least. 



3. The smallest ova are as large as millet ; the ova are 

 not continuous with the perforation, but in the middle. 

 For two divisions extend on each side, from the tail 

 and from the thorax, and this is also the line of junction for 

 the opercula. The ova, which are placed at the side, cannot 

 be enclosed, unless the extremity of the tail is drawn over 

 them ; this, however, covers them like a lid. 



4. The female, in depositing her ova, appears to collect 

 them on the cartilaginous appendages by means of 

 the broad part of the folded tail. She produces them 

 by pressing with her tail and bending her body. These 

 cartilaginous processes at the season of oviposition in- 

 crease in size, in order to become appropriate recep- 

 tacles for the ova. The ova are deposited on these pro- 

 cesses, as those of the sepia are deposited upon broken 

 pieces of wood or anything floating in the sea. This is the 



