242 SYNOPTIC COLLECTION. 



illustration shows the exquisite delicacy of Hyalea globu- 

 losa Rang with its blue shell and softly tinted wings. In 

 this species the shell (No. 568) is nearly globular with 

 the' dorsal part projecting in front (PL 569) and the ven- 

 tral part convex. 



Hyalea tridentata Lam. (No. 570), is a much larger 

 species with a golden shell (No. 571) and purple and 

 golden wings (PI. 572). The upper and lower parts of 

 the shell, and the open spaces between the two are seen 

 in the side view (PI. 572, figure on the right). 



Cleodora cuspidata Bosc. is protected by a glassy, nearly 

 transparent shell (No. 573) with three projecting spikes. 

 The visceral mass is colored in the figure (PL 574), while 

 the other parts are nearly colorless. The alcoholic speci- 

 mens (No. 575) show different ages of another species, 

 Cleodora pyramidata. 



Balantium recurvum Child (No. 576), is one of the 

 larger Pteropods. Its shell is triangular in shape and 

 terminates in a sharp point. Its delicate coloring and 

 symmetrical transverse markings make it a beautiful 

 object. 



Gymnosomata. The larva of Cfio, a member of the 

 Gymnosomata, loses its primitive and secondary shell and 

 its velum after which a second larval form appears with 

 three bands of cilia encircling its body. This second 

 larva is without a mantle and secretes no shell. 



The adult (No. 577, alcoholic specimen ; PL 578, Clio 

 ( = Clione) borealis Pdron) has a long body with a distinct 

 head. The latter bears two pairs of tentacles which are 

 provided with a vast number of tiny suckers. The wings 

 are distinct from the head and do not join in front, in 

 which particulars the Gymnosomata differ from the The- 

 cosomata. The foot is also distinct from the wings and 

 consists of a posterior lobe with two smaller anterior ones. 

 In all these forms the anus is on the right instead of the 

 left side of the body. 



Pneumodermon peroni Q. & G. loses its mantle and shell 



