1897] 



FOSSIL APODIDAE 



390 



limbs (see fig. 6), each pair being provided with a pair of abdominal 

 sanslia. It was, of course, more or less of an assumption that these 

 limbs and ganglia represented true segments, because to all appear- 

 ance the true segments are marked off on the body as shown in the 

 fio\ 6. Further, authors were not wanting who definitely claimed 

 that the apparent segmentation was the true one, and that the 

 multiplication of the limbs, as many as four, five, and even six to 

 one single segment, was due to some kind of secondary reduplication 



] . Protocaris marshi, Walcott ; 2. Dipeltis carri, Schuckert ; 3. Dipeltis diplocliscus, 

 Packard ; 4-5. Another specimen of the same, showing the under surface and part 

 of the upper with the eyes ; 6. Apus glacialis, var. spitzbcrgensis from the side, 

 with left half of the carapace cut away to show the whole trunk ; bp. left limbs of 

 the eleventh segment modified into a brood-pouch, p. pore leading into the water 

 sacs over the eyes. [Figs. 1-5 after Schuchert.] 



of organs on one and the same segment. The present writer, on the 

 contrary, maintained that, as at the front end of the body each pair 

 of limbs with its pair of ganglia corresponded with a true body seg- 

 ment, the whole series of the limbs should be taken as true seg- 

 mental structures, and where, after the eleventh segment, marked 

 by its brood pouch (hp.), the limbs begin to diminish in size, there 

 being more than one to each external division of the body, these 



