A note on the biology of the Lamellibranch Rocellaria (Gastrochaena) cuneiformis Spengler
- 1 The well known generic name Gastrochaena has been applied to the genus formerly known as Fistulana Brug. Consequently the genus formerly known as Gastrochaena Spengler 1783 is now referred to as Rocellaria Blainville 1828.
- 2 Specimens of R. cuneiformis Spengler were obtained from burrows in coral and were studied alive at Raffles Light, Singapore.
- 3 Studies were made of the siphons, the shell, the musculature, the ciliary mechanisms on the structures in the mantle cavity, and also the internal structure and function of the stomach.
- 4 Comparisons were drawn between Rocellaria and other rock-boring genera in the family Pholadidae. The most striking feature noted in this comparison was the presence in Rocellaria of a shell process at the anterior end of the hinge, on to which the anterior byssus retractor muscle was inserted. This is analogous, if not homologous with the apophysis of the Pholadidae and Teredinidae.
- 5 There are striking differences between Rocellaria and the Pholadidae in the method of rock-boring; a stomach appendix, and an accessory visceral ganglion, both present in the Pholadidae, were found to be absent in Rocellaria.
- 6 It was concluded that various similarities between Rocellaria and members of the order Adesmacea (Teredinidae and Pholadidae) arose as functional responses to a common mode of life, and are insufficient to indicate that the Gastrochaenidae should be regarded as an early offshoot from the lineage that gave rise to the Adesmacea.