characterized by numerous small to medium- 

 sized vacuoles (Fig. 2C). 



Differences between feeding-treatments in 

 the gross morphology of the digestive gland 

 were dramatic (Fig. 3). The digestive glands of 

 squids that had been raised on zooplankton were 

 thin-walled, with large fluid-filled lumina 

 traversed by thin lamellae (Fig. 3A). The diges- 

 tive glands of squids raised on DOM (Fig. SB) 

 appeared to be much more robust and well devel- 

 oped, with thick tissue and many small tubules. 



Numerous small-to-large vacuoles were found 

 in even the smallest of the field-collected L. 

 pealei (Fig. 4A). Digestive-gland tissue was 

 thick, although a large central lumen was pres- 

 ent. The internal yolk sac remained in one squid 

 of 2.0 mm dorsal mantle length (DML). In larger 

 L. pealei (Fig. 4B, C), vacuoles were numerous 



and of various sizes but the digestive-gland tis- 

 sue varied in thickness. In the largest squids 

 examined, tissue growth had filled most of the 

 lumen so that it was characterized by many 

 smaller tubules, similar to those in Figure 4C. 

 These larger paralarvae had few vacuoles but 

 those present were large. 



Discussion 



Whereas L. forbesi has large hatchlings that 

 can be reared in the laboratory (Hanlon et al. 

 1985), paralarval L. forbesi are seldom collected 



f 



„ '*-■;* ■■"^^ft^' 



1 A 



Figure 3. — Digestive glands of laboratory-reared Loligo 

 forbesi, > 1 week old: A, 4.0 mm DML, from a container 

 with zooplankton food organisms present; B, 4.2 mm DML, 

 from a container with elevated concentrations of dissolved 

 organic matter. Scale bar = 500 \i.m. 



Figure 4. — Field-collected Loligo pealei paralarvae: A, 2.0 

 mm dorsal mantle length (DML): B, 3.0 mm DML; C, 3.4 

 mm DML. Scale bar = 100 p-m. 



998 



