350 



LOWER INVERTEBRATES. 



scavengers, feeding almost entirely on dead and decaying animal matter. The shell 

 has a sharp conical spire, the outer lip is expanded, and usually is notched near the 

 anterior canal. 



The genus Strombus has the outer lip entire, with the exception of the notch 



mentioned above, and the aper- 

 ture is long and narrow. In the 

 young the outer lip is small, and the 

 shell looks like that of a cone, but as 

 the period of maturity is approached 

 it becomes flared out. Species of 

 the larger wing-shells are among 

 the most common ornaments, large 

 numbers being bi'ought from the 

 West Indies. In the United States, 

 the species most commonly seen is 

 Strombus gigas, a West Indian form, 

 with a delicate red or pink intei-ior. 

 As the name indicates, this is one of 

 the largest members of the genus. 

 Another species common on the 

 Florida reefs is S. pugilis, the gen- 

 eral appearance of which may be 

 seen from our figure. 



Allied to Strombus are the scor- 

 pion shells forming the genus Ptero- 

 cera. In early life the shells are much like those of the strombs, but when approaching 

 the adult condition the long finger-like processes of the 

 mantle begin the secretion of shelly matter, so that the 

 outer lip is armed with a number of strong horns. At 

 first these horns are channeled, but later in life they be- 

 come solid. In some they are short and straight, but in 

 others they are considerably bent. All the species come 

 from the Indo-Pacific regions. In Hostellaria, which has 

 much the same distribution, the shell is much like that of 

 Fusus, the spire and the anterior canal being longer than 

 in Pteroceras, while the horas of the aperture ai-e very 

 much smaller. Rostellaria moves about in the same 

 manner as do the strombs, but some species are more 

 timid. It is an inhabitant of deeper water than the 

 other. The only other oriental genus which we will 

 mention is Terebelhcm the species of which live in deep 

 water. They are very active and at the same time very 

 timorous. "It will remain stationary for a long time 

 when, suddenly, it will roll over with its shell, and con- 

 tinue again perfectly quiet." At other times they will 

 leap several inches from the ground, like species of Strombus. In some species one 

 of the ocular peduncles is longer than the other, and this one is used almost exclu- 

 sively. As in the strombs, the iris is colored and the pupil black. Aporrhais con- 



FiG. 457. — Strombus lentiginosus. 



Fig. 458. 



Pterocera chiragra^ scor- 

 pion shell. 



