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crVi 



Nachdruck verboten. 



Vestiges of the Thyroid in Chlamydoselachus anguineus, Scyl- 

 lium catulus, and Scyllium canicnla. 



By T. GooDEY, M. Sc. (Birm.), 

 Research Scholar Zoological Laboratory, University of Birmingham. 



With 4 Figures. 

 1. Chlamydoselaclius anguineus. 

 Whilst prosecuting a piece of research on the skeletal anatomy 

 of the primitive selachian Chlamydoselachus anguineus, I encountered 



an interesting tubular structure 

 in connection with the thyroid 

 gland of this fish, and I propose 

 in the first part of the present 

 communication to deal with the 

 structure and relations of this 

 tube. 



The thyroid gland, appearing 

 as a pinkish compact mass of 

 tissue, was found occupying an 

 oval concavity {th.c. Fig. 1) on 

 the ventral surface of the basi- 

 hyal cartilage, hh. 



In removing the mucous 

 membrane from the dorsal, or 

 oral, surface of the basihyal 

 cartilage, a narrow tube was cut 

 across transversely, and in tracing 

 this backward and downward it 

 was found to pass through the 

 foramen (/) and to become at- 

 tached to the anterior end of 

 the thyroid gland. The inside 

 of the tube, when touched with 

 a needle, had a rough feel, and 

 the lining appeared to carry small 

 dermal spines or denticles. 

 In order to investigate its minute structure and to determine its 

 relation to the thyroid gland with which it evidently had a very in- 



Fig. 1. Ventral view of mandibles, 

 basihyal cartilage etc., of Chlamydoselaclius 

 anguineus. ®/,g nat. size. bh. basihyal. crb.l. 

 ceratobranchial 1. crh. ceratohyal. /. foramen. 

 m. mandible, rh.e. thyroid concavity, v.a. 

 ventral aorta. 



