XX 



A MONOGRAPH OF THE 



Fam. 4. Dyphyllidiadce. 

 Gen. 18. Diphyllidia, Cuv. Cloak exposing the head, coriaceous; ten- 

 tacles laminated longitudinally, approximated, partially retrac- 

 tile within a common cavity ; veil reflected ; branchiae of two 

 kinds, the anterior longitudinally folded, the posterior trans- 

 versely. Tongue broad, with numerous simple lateral spines 

 and a denticulated central spine. Corneous jaws 



TYPE. 



D. lineata, Otto. 



Section 2. With the branchise on the upper side of the cloak. 



Fam. 5. Tritoniadce. 



Gen. 19. Tritonia, Cuv. Branchise plumose; tentacles 2, fasciculated, 



retractile within plain sheaths ; veil digitated. Tongue broad, 



with numerous simple or denticulated lateral spines, a tricuspid 



central spine, and a broad plate on each side of it. Large 



corneous jaws "... 



Fam. 6. Scyllceidce. 

 Gen. 20. Scyll^ea, Linn. Branchiae plumose, scattered over the lateral 

 lobes on the inner surface ; veil small ; tentacles 2, laminated, 

 with large compressed sheaths. Tongue broad, with numerous 

 lateral spines and a central spine, all denticulated. Large 

 corneous jaws 



T. Hombergii, Cuv. 



S. pelagica, Linn. 



Tribe 2. Liver diffused ; branchise papillose, simple or branched. 

 Section 1. With a posterior central gastro-hepatic vessel; reproductive organs with a 



single external orifice. 

 a. With the posterior vessel of the gastro-hepatic system below the ovary. 



Fam. 7. Dendronotidce. 

 Gen. 21. Dendronotus, A. and H. Body compressed, without cloak; 



branchiae ramose; veil branched; tentacles laminated, with 



branched sheaths. Tongue rather narrow, with several lateral 



spines, and a larger central spine, all denticulated 

 Gen. 22. Bornella, Gray. Body compressed, without cloak; tentacles 



2, retractile within branched sheaths ; front of the head with 



2 stellated or fimbriated appendages; branchiae plumose, 



arranged on plain branched pedicles. Tongue? 

 Gen. 23. Lomanotus, Ver. Body subquadrilateral ; branchiae papillose or 



foliaceous, arranged in a nearly continuous line on a pallial 



margin ; tentacles 2, laminated, with sheaths. Tongue broad, 



with numerous denticulated spines ; no central spine. Corneous 



jaws ..... 



Gen. 24. Hero, Lov. Cloak wanting; tentacles 2, linear, simple, non- 

 retractile ; veil rather large, plain, produced at the sides ; 



branchiae branched or umbellated. Tongue with a large central 



denticulated spine, and 2 simple lateral spines. Corneous jaws H. formosa, Lov, 



D. arborescens, Mull. 



B. digitata, Adams. 



L. Genei, Ver. 



