648 



MOLLUSCA 



SUB-KINGDOM VI 



cestes, but differing in that the sutures have broad entire ventral saddles and broad 

 rounded lobes ; or if the latter are angulated, they are incomplete internally, rising to 

 saddles at the lines of involution. Siphuncle tubular and small, and funnels com- 

 paratively short (G umbel). 



Cyrtoclymenia (Fig. 1116), 

 Oxyclymenia (Fig, 1117), 

 Giimbel ; Platyclymenia, 



JJvatt Devonian 



- ' 



1 amily 2. Cymacly- 

 menidae. Giimbel (emend). Conchs similar to those of preceding family, but sutures 

 have two pairs of lateral saddles, and there is a ventral lobe with a median saddle. 



Cymaclymenia (Fig. 1118), Sellaclymenia, Giimbel. Devonian. 



Family 3. Gonioclymenidae. Conchs differ from preceding families in that 



Suture -line of Cyrtocly- 

 tnenia laevigata, Miinst. sp. 



FIG. 1118. 



Suture -line of Cymaclymenia striata 

 Miinst. sp. 



FIG. 1117. 



Oxydymenia undulata, Miinst. sp. 

 Upper Devonian; Elbersreutli, 

 Fichtelgebirge. 



IMC. 1110. 



Gonioclymenia spa-io*", .Miinst. sp. Upper 

 vonian ; Schiibelhaininer, Fichtelgebirge. 1/2- 



the sutures have deep undivided ventral lobes, and sometimes two pairs of lateral 



saddles are present. These last may be either in part or wholly divided by marginals. 



Gonioclymenia (Fig. 1119), Cycloclymenia, Discoclymenia, Giimbel; Cryptodymt'n'm, 



Hyatt ; Acanthoclymenia, gen. nov. Type A. (Clym.} neapolitana, Clarke sp. Devonian. 



Sub-Order B. MICROCAMPYLI. Hyatt. 



Bactriticones, mimoceracones, and ammoniticones. Sutures entire, and have slight 

 undivided lobes on the venter, and but one pair of broad, shallow lateral lobes in primitive 

 forms. AntisipJwnal lobe absent in these, and the dorsal suture has a median saddle, but 

 this becomes divided by a small antisiphonal lobe in some forms. In more specialised 

 shells (Pinnacites) the lateral lobes become divided into two pairs and the dorsal saddles 

 disappear, being replaced by two corresponding lobes, and the septa become at th< .^inn- 

 time biconcave. Siphuncle subventran, and apparently without calcareous sheath. 

 Funnels narrow, monochoanitic, often long, but never perfectly holochoanitic. Ventral 

 lobes V-shaped, and remain undivided so far as known. Aperture with hyponomic */// x. 



Family 1. Bactritidae. Bactriticones and cyrtoceracones, usually 

 elliptical in section, and connecting through Protobactrites with the Nautiloidxi. 



