THE INTERNAL ANATOMY OF TWO PHALLOSTETHID FISHES

¹ From the Marine Biological Laboratory, Woods Hole, Mass., and the Department of Zoölogy, Smith College

The anatomy of the soft parts of two phallostethid fishes, Phenacostethus smithi and Gulaphallus mirabilis, has been studied.

1. Two groups of vestigial fin rays are present on the copulatory organs of Gulaphallus but are lacking on that of Phenacostethus.

2. A tuft-like pseudobranch, belonging to Granel's type II, is present in both species.

3. The viscera are located almost entirely anterior to the air bladder, and digestive, reproductive and excretory systems open externally on the sub-gular copulatory organ in the male and on the ventral surface of the gular region in the female. Liver, pancreas, spleen, thymus and thyroid are identified.

4. Neuromasts are scattered on the surface, and four canals, probably of the lateral line type, are present on the heads of both species.

5. The kidney contains one pair of pronephric glomeruli which may be functional. There are 13-18 mesonephric glomeruli in Phenacostethus, and 33-38 in Gulaphallus.

6. The ovary is single in both species and contains a relatively small number of ova. The oviduct, continuous with the ovary, is thick-walled and muscular.

7. The testis is a single mass. Seminiferous tubules open into a collecting tubule which continues as the ductus deferens. This duct forms a large coiled mass in Phenacostethus and is lined by simple columnar epithelium. Homogeneous globules, present among the sperms in the lumen, do not appear to form spermatophores. The ductus deferens in Gulaphallus is very narrow within the body cavity, but dilates to form a seminal vesicle in the copulatory organ.