MORPHOLOGICAL NOTES. 



21 



2. The integument 



In Tullbergella (fig. 27) and Stebbingella (fig. 3) the integu- 

 ment is very thick and hard, and calcareous; in the latter it shows many 

 tubercles, fine notches, scrolls and grooves; in Oxycephalus (fig. 4) the 

 integument is thinner, sometimes forming longer or shorter longitudinal 

 and transversel keels or folds, but these keels are only angulated eleva- 

 tions of the integument, not formed by calcareous deposits as in the two 

 above mentioned genera. In Cranocephalus, (fig. 5) Dorycephalus, 



Fig. 3. Stebbingella 

 Theeli. . 



Fig. 4. Oxycephalus Clausi. 



Fig. 5. Cranocepha- 

 Im Goesi. cf- 



Leptocotis and Xiphocephalus, the integument is still thinner and not 

 at all calcareous, showing in some species small epidermal grooves which 

 will be spoken of under the head glandsy> below. The hypodermis seems 

 to be either composed of hexagonal cells, or hexagonally reticulated 

 but this reticulation is seldom to be seen distinctly; at the head, the 

 epirnerals, and parts of the ural appendages it is most distinct. 



The colour is very variable, red, yellow, green, and white; many 

 species are entirely hyaline. Only in Tullbergella cuspidata, and 

 in Xiphocephalus White i, have I observed larger pigment-cells, or 

 chromatophors of some kind, of more or less regular star-like form. There 

 are also to be seen separate calcareous (?) concrements in the shape of small, 

 irregularly ovate discs or buttons in the thin integument of some species 

 of Oxycephalus; in the thick, calcareous integument of Tullbergella 

 they are very numerous. 



