THE OSTEACODA. 



291 



net to the surface from the horizon where it has been fishing ; were this so, the results 

 at 75 fathoms shoukl be intermediate between those at 50 and 100 fathoms; as a fact, 

 they are often not so. The same relation has been noticed in some species at a hio-her 

 level, 25 and 75 fathoms having a preponderance of specimens over 50 fathoms. 

 A possihle explanation is suggested on p. 303. 



The a LARViE. 



Though the exact attribution of the individual specimens may in some cases be 

 uncertain, there can be little doubt that the majority of these larvae can be safely assigned 

 to magna, apart from the morphological grounds dealt with in the Systematic Part. 

 Of the total specimens * of the five species likely to have been represented by larvee 

 of this general type, magna formed 87 per cent., zetesios 1, Jiyalophyllum 6, loricata 3, 

 spinirostris 1 per cent. Under the reasonable supposition that the relation of larvee 

 to adults is anything like proportional in the different species, it is probable that by far 

 the larger number belonged to magna. With the reservation that a small percentage 

 may have belonged to other species, the A larvae are here attributed to magna for 

 statistical purposes. 



At 



Between 







2.5 



50 



75 



]00 



150-50 



200-100 



250-150 



300-200 



400-300 



500-400 



750-500 



1000-750 



1250-1000 



1500-1250 



fathoms 

 this species 

 occurred iu 



23 pel- cent, of 13 hauls, with O'TG 



The distribution appears to be much the same as that of magna : that is to say, these 

 larvae were plentiful in the epiplankton and down to about 200 fathoms ; below this 

 depth their scarcity, as compared with the large numbers at higher levels, probably 

 indicates that the few specimens captured were dead or dying. 



But there is a slight difference from the corresponding table in magna, in tliat a 

 distinct plurimum is observed at 75 fathoms ; further, the slight rise In population at 

 about 750-500 fathoms which is noticeable in several other species is not clear here, 

 though there is a marked droj) in the captures below 750 fathoms. 



SECOND SERIES. 



* Actual numbers, comparable hauls, epiplankton. 

 -ZOOLOGX, VOL. X. 



47 



