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posterior lateral cartilage (where the basilaris attains its maximum 
bulk) becomes confluent along its outer lower edge with the basilaris 
attains its maximum bulk) become confluent along its outer lower edge 
with the basilaris of its own side (fig. 36). Still more posteriorly each 
band splits into an outer and an inner half—the outer half completely 
fuses with the basilaris and terminates posteriorly by attachment to the 
styloid process; the inner half, on the other hand, becomes confluent 
with the anulo-glossus (XVI) and copulo-glossus rectus (XJ) muscles 
towards the extreme end of the piston cartilage and like them is 
inserted laterally into this cartilage (fig. 37). As P. FÜRBRINGER points 
out, the basilaris very largely forms a support for the walls of the 
cavity lined by the pharyngeus and containing the throat passage, 
hyomandibulari-glossus muscles and longitudinalis linguae tendon 
(fig. 36). The massive sides of the basilaris (VII) form efficient 
lateral supports and the ventral muscle band (XXJ) with the piston 
cartilage a substantial floor. The basilaris only extends dorsally in 
front of the eye and there only as far as is represented in fig. 25. 
Its function, as P. FÜRBRINGER remarks, is very similar to that of the 
anularis surrounding the buccal funnel, since during the process of 
swallowing food (a sucking action) it takes both an active part in 
contracting the throat cavity and a passive part in maintaining its 
distension against external pressure. Ventral to the basilaris we have 
the stout elongated anulo-glossus (XVJ) and copulo-glossus rectus (XJ) 
muscles. The former lies immediately under the ventral portions of 
the anterior sub-branchial myotomes and in the figure (20) is repre- 
sented as being without its middle portion (in order to expose the 
basilaris and the copulo-glossus rectus). Anteriorly it is attached by 
a strong short tendon to the side of the anular cartilage; posteriorly 
it becomes confluent with the copulo-glossus rectus and hypoglossus 
to form a large muscular mass which is strongly inserted into the side 
of the posterior portion of the piston cartilage (fig. 21). All these 
three muscles serve to draw forward the rasping piston apparatus in 
the act of feeding. The copulo-glossus rectus (XJ) is a larger and 
thicker muscle than the last-named and is strongly attached to the 
lateral process (M.V.) of the median ventral cartilage. This last- 
named portion of cartilage is firmly connected with the anular 
cartilage by the thick tendon already mentioned—the copulo-anularis 
ligament (C.A.L.). The posterior attachment of the copulo-glossus 
rectus to the side of the piston cartilage has just been described. 
