THE CEPHALOPODA 301 



pair of salivary glands is relatively slightly developed, and is 

 conspicuous only in the Oigopsida (Spirilla, Ommatostrephidae, Fig. 

 282, II, Onychoteuthis, Veranya, Gonatus, etc.). In the Myopsida, 

 however, there is an unpaired intra-bulbar glandular mass, lying 

 behind the radula at the entrance of the ' oesophagus, and this 

 corresponds to the embryonic condition of the anterior salivary 

 glands of the Oigopsida and Octopoda. The last-named have also 

 two pairs of well-developed salivary glands. The anterior pair 

 consists of two flattened acinous glands attached to the posterior 

 surface of the buccal bulb, their short ducts opening on either side 

 into the postero-lateral part of the pharynx. The topographically 

 posterior or abdominal glands are absent in Cirrhoteuthis, but in 

 other Octopoda they are present, and are relatively larger than the 

 similar pair in the Decapoda, but have the same structure and 

 relations, save for the fact that they are situated farther back near 

 the oesophageal proventriculus. The secretion of the posterior 

 salivary glands of the Octopoda contains a proteolytic ferment and 

 is poisonous ; the secretion of the corresponding glands of Sepia 

 contains, in addition, a diastatic ferment. 



In addition to the salivary glands proper, all theDibranchia possess 

 a sub-lingual gland in front of the sub-radular organ. It is of small 

 size and is formed by the infolding of the epithelium of this region. 



The oesophagus is long in all the Cephalopoda, and it may be 

 enlarged to form a crop or proventriculus : this enlargement is 

 gradual in Nautilus (Fig. 270, oe, cr), abrupt in the Octopoda, with 

 the exception of Cirrhoteuthis, but in the Decapoda the oesophagus 

 is of the same diameter throughout (Fig. 268, oe). The true 

 stomach is a more or less globular or elongated pouch, with fairly 

 thick muscular walls, and is situated at the summit of the visceral 

 mass (Fig. 271, gizz) : its two orifices, the cardiac and the pyloric, 

 are anterior. 



At the initial part of the intestine, close to the stomach, is a 

 thin-walled caecal diverticulum of various shape. It is spherical in 

 Nautilus, Eossia, and Leachia, elongated and much larger than the 

 stomach in Loligo, but it is more frequently coiled in a spiral, 

 like the spiral caecum of sundry rhipidoglossate and other Gastro- 

 poda ; such is the case, for example, in Spirula (Fig. 268, p.s), 

 Ommatostrephes (Fig: 269, e), Sepia, and the Octopoda. The hepatic 

 ducts open into the stomachal caecum. 



The liver is formed by two symmetrical glands, which are 

 separate from one another during development (Sepia), but are 

 generally partially fused together in the adult. This organ 

 exhibits its minimum state of concentration in Nautilus, consisting 

 of four lobes, each with its proper duct. In the Dibranchia the 

 liver is more compact and consists of two lateral lobes, which are 

 only united to a small extent near the middle of their length in 



