Pimctiims of the Limnoria Terebrans. 3^^ 



the globules which are found within the abdominal cavity of 

 many marine Annelida, and which vary from g\^th to yj^th 

 of an inch in diameter. Of the oviducts, and the arrangement 

 of the ova before their maturation, I know nothing ; but I 

 have frequently found, both in autumn and in spring, the foetus 

 within the abdominal pouch, which I have already mentioned 

 as existing in the female. This pouch is formed of eight or 

 ten scales, hanging in pairs from three or four segments between 

 the third and the seventh. Their general disposition is shewn 

 in Fig. 2 ; their form is ovate ; their edges are united, probably 

 by an internal membrane lining the sac. Within the sac thus 

 formed, there are generally found six or seven young limnoriae, 

 in some individuals only five, in others nine. They have come 

 under my observation always in an advanced stage of develop- 

 ment, but I have never seen them give any signs of life. The 

 head and the other five anterior segments are larger proportion- 

 ally than in the adult. The antennse and eyes are almost com- 

 pletely formed, although the articulations of the former are not 

 distinctly seen. The colour of the eye is nearly as deep as in 

 the adult ; the other appendages hang loosely from the inferior 

 surface : all present the appearance of simple tubiform organs. 

 Even the jaws and the branchiae can scarcely be distinguished 

 from the legs. There are representations of the dorsal and late- 

 ral aspects of the foetus given in Figs. 17 and 18. 



///. — Performance of Functions and Habits. 

 Observations are awanting to shew to what extent the Lim- 

 noria enjoys, and in what mode it exercises, the functions of sen- 

 sation. When any part of its body is touched rudely, it rolls 

 itself up almost into a spherical form ; approximating for a few 

 seconds the head and the tail, by incurving the inferior surface, 

 in the same manner as is done in similar circumstances by seve- 

 ral animals, both terrestrial and marine, which resemble it in 

 structure ; particularly by Sphaeroma serrata. Typhis ovoides, 

 and the medicinal wood-louse. Armadillo vulgaris. 



While creeping, the Limnoria moves its inferior antennae in 

 all directions, and seems to be very sensible to the least impres- 

 sion made upon them ; but the superior pair are generally fold- 

 ed back upon the head above the eyes. 



