176 
P.R. PUGH 

Fig. 8 Erenna laciniata. A. upper and B, lower views of mature nectophore. Scale 5 mm. 
On each side there was a thickened flap that lay ventrally and was 
directed toward the mid-line. On smaller, younger nectophores 
(Fig. 9) the thrust block consisted of two small protuberances sepa- 
rated by a U-shaped indentation. 
The main ridge system was well delineated, especially in the 
younger nectophores (Fig. 9). It consisted of pairs of infra- and apico- 
lateral ridges, which united close to the lateral apices of the axial 
wings; and a short pair of vertical laterals connecting them (Fig. 8), 
although, in younger nectophores, the junction with the apico-laterals 
was indistinct (Fig. 9). The infra-laterals ended, basally, on either side 
of the ostium. The apico-laterals remain prominent until just above 
ostial level. In younger nectophores, close to the ostium, the apico- 
laterals gave rise to three very vague, but broad branches (Fig. 9A). 
However, in mature nectophores only after staining could two very 
vague ridges be discerned (Fig. 8A). These would be virtually 
impossible to see in damaged or poorly preserved material. 
No obvious mouth plate, and ostial opening basal. Prominent 
protuberances on each side of the ostium which bore strips of 
distinctive epidermal cells, and another triangular patch in mid-line 
on dorsal side of the ostium. In addition, a relatively large patch of 
such cells was present on each side of the nectophore, at about the 
mid-height of, and immediately basal to, the vertical lateral ridges 
(Figs 8A, 9A). All these patches are believed to be sites of bio- 
luminescence. 
T-shaped nectosac with a distinct muscle-free zone at its apex. 
Short pallial canal, originating at the base of the thrust block, with a 
long pedicular canal, which on reaching the nectosac gave rise to the 
four, straight, radial canals. In the younger nectophores there were 
obvious signs of thickening of the lateral radial canals in the apico- 

Fig.9 Erenna laciniata. A. upper and B, lower views of immature 
nectophore. Scale 2 mm. 
lateral region of the nectosac, but these were difficult to discern in 
the mature ones. No small protuberances, or ‘horn’ canals, were 
present. In the JSL material the radial canals had no obvious 
pigmentation, although in other nectophores, which are tentatively 
referred to this species, they could have an orange hue. 
SIPHOSOME. On collection the siphosome of both specimens was 
tightly contracted. The gastrozooids and the terminal processes to 
the tentilla were lightish brown in colour; while the palpons were 
suffused with brown pigment. 
BRACT. (Fig. 10). Over 1000 bracts, of two types, were found with 

Fig.10  Erenna laciniata. Bracts. A., B. dorsal views of first type; C., D. 
dorsal views of second type. Scale 5 mm. E. Immature bract. Scale 1 mm. 
