6 OKHAMANDAL MARINE ZOOLOGY— PART II 



successful in the case of Buccinum are ineffective here, and the aid of a sledge hammer 

 has to be evoked if we require to dissect the animal. 



The ova are deposited in a many-chambered chitinous egg-capsule of striking and 

 peculiar appearance. In general form it is an elongated loosely spiral annulated 

 cylinder, divided transversely by partitions into a number of compartments ; it reminds 

 one of a corrugated and loosely twisted ram's horn. When newly formed it is pale 

 opaque yellow in colour ; with age it darkens and becomes covered with low growths 

 of algae. It stands upright on the sea-bottom, the lower and first formed end rooted in 

 the sand by means of a broad flange-shaped basal disc. The lower end is narrow, the 

 chambers there small ; these gradually increase in size, till at a point about one-third 

 of the length from the base they attain a maximum size, which is maintained thence 

 to the abruptly truncate summit. 



Considerable complexity is introduced by the fact that the partitions between the 

 chambers are double and separated by a slight space except along the hinder edge. 

 The partition which forms the floor of each compartment has a crescentic slit parallel 

 with the front edge, hence when the capsule sways to the current the partitions 

 between the chambers gape slightly and so allow a circulation of sea-water within 

 each compartment, thus providing the aeration needed by the larvae. The transverse 

 partitions are much thinner than the outer wall of the capsule. 



In each chamber a considerable number of fertilised ova are deposited, embedded 

 in a transparent colourless gelatinous nutritive matrix which entirely fills the chamber. 

 In this nutritive jelly, the stronger of the embryos develop rapidly ; in each 

 chamber an average of six reach the larval stage characterised by the possession of 

 a larval external shell or protoconch ; those that do, grow rapidly and soon pass 

 beyond the protoconch stage, and assume the semblance of adult form provided with 

 a brown-flecked shell measuring eventually slightly over half an inch in length, 

 inclusive of the two and a half whorls of the protoconch which persists both here and into 

 adult life. By the time this size is attained all the nutritive contents of the incubatory 

 chamber, including the remains of the weaker of the brethren, have been eaten up 

 by the ravenous young who now find it necessary to leave home in search of food. Their 

 first step is to eat through the partitions dividing the chambers, a proceeding that results 

 in the bringing together of the whole surviving family numbering usually from 200 to 

 250 in aU. The stronger next eat a way through the outer wall and the whole brood 

 follow to scatter over the adjacent sea-bottom to lead independent lives. 



The breeding season, when the capsules are fashioned and rooted in the sand, extends 

 throughout January, February and the first half of March. Some divers assert that new 

 capsules are also to be found in June and July, but I have had no opportunity to test 

 this statement. The sexes being separate the divers have several stories to tell anent 

 the breeding habits. Among others they assert that the females are the larger and are 

 attended each by a number of smaller males, who assist in the making of the capsule 



